OFFSET
1,1
COMMENTS
Prime digits are 2, 3, 5 or 7.
MATHEMATICA
snpdQ[n_]:=Count[IntegerDigits[n], _?PrimeQ]==Count[IntegerDigits[n+2], _?PrimeQ]; {#, #+2}&/@Select[Prime[Range[100]], snpdQ]//Flatten (* Harvey P. Dale, Dec 04 2017 *)
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
Juri-Stepan Gerasimov, Mar 15 2009
EXTENSIONS
(13,15) inserted, (23,25) inserted, and all other numbers replaced by R. J. Mathar, May 19 2010
Definition changed to match the terms by N. J. A. Sloane, Dec 03 2017
STATUS
approved